Vehicle steering wheel and column assemblies have been extensively engineered to provide desirable steering characteristics. Conventional steering wheel and column assemblies may still permit minor torsional vibrations to be transmitted through the steering column shaft to the steering wheel. Such vibrations may be produced by various periodic sources at the rotating corners of the vehicle, such as the tires, wheels, brake rotors, bearing hub assemblies and the like, in response to such conditions as imbalance and non-uniform tires. The vibrations may be produced even when the vehicle is traveling over a relatively smooth road.
This vibratory condition may be characterized by the unwanted dynamic rotational movement of the steering wheel at or above thresholds perceptible to a driver. Although this rotational movement is relatively minor, it is readily perceptible to a driver and consequently undesirable. A mass damper may be incorporated in a steering wheel to dampen the vibration by either adding a mass on the steering wheel armature or using the driver airbag or the inflator itself as the mass dampening device. However, a mass damper may be limited by design to anticipate a range of frequencies.
Traditional steering wheel mass dampeners are tuned to dampen one frequency of vibration in a single position that may be referred to as a mid-mid position of the steering column. The frequency of vibrations may change if the steering column is adjusted away from the mid-mid position, such as when a telescopic or tilt feature on the steering wheel is adjusted, which may increase vibrations as the steering wheel and column is extended towards the driver.